Locking member for sprinkler heads



y 3- G. 1. ROCKWOOD 1,909,123

LOCKING MEMBER FOR SPRINKLER HEADS Filed Dec. 18, 1929 6&0 e [206% A458 Patented May 16, 1933. 3

@UNITED STATES PATENT. OFFICE,

GEORGE I. ROCKWOOD, OF WOBCESTER MASS ACHUSETTS, ASSIGNOR TO ROCKWOOD SPRINKLER COMPANY OF MASSACHUSETTS, OF' -WORCESTER, MASSACHUSETTS, A

; CORPORATION or MASSACHUSETTS LOCKING 11mm FOR SPRINKLER, mamas Application filed December 18, 1929. s mi in. 415,008.

mal element, being held under light compression, thereby permits a low-melting alloy to be utilized in an arrangement of parts which promotes sensitiveness in operation. To this end the thermal element and its support ing structure is directlyex-posed to a rising current of hot air when the device is in use in a sprinkler head.

My invention further relates to arrangementsand combinations of parts which will be hereinafter described and more particularly pointed out in the. appended claims.

A preferred form of the invention is shown I in the drawing, in which Fig. 1 is a side elevation ofa sprinkler head embodying my improvements;

Fig. 2 is a sectional side elevation of my 1 improved lockingmember Fig. 3 is a plan VIEW thereof, looking in A thedirection of the arrow 3 in Fig. 2;

. i Fig.4 is an end elevation thereofplooking in the direction of the arrow 4 in Fig. 2;

Fig. 5 is a perspective view ofj'theretaining device; 1

Fig. 6 is a bottom view, looking in the direction ofthe arrow 6 in Fig. 2;

Fig. 7 is a perspective view of the thermal element; and

Fig. 8 is a side elevation showing the parts,

released. I

While adaptable to fire door links and other uses, my improved locking member is particularly designed for use in sprinkler heads, a common form of which is shown in Fig. 1

A threaded member or nipple 10 is providedwith a cap or closure 12 functioning as a valve held in place by a post 14 engaging one end of a lever 15. A locking mem,- her or strut is interposed between shoulders at the lower end of the post 14 and at the outer end of the lever 15. A compression 7 screw 17 engages the upper side of the lever 15 at a point slightly out of alignment with the post .14. The screw 17 and a spreader plate 13 are mounted on a frame structure 20, pro ecting upward from. the threaded member or nipplelO.

My present invention is not concerned with the general structure of the-sprinklerhead but relatesmore specifically to the structure of an lmproved locking member or strut for holding the post 14 and lever 15 in position to firmly seat the cap or closure 12.

My improved locking member comprises two thrust members 30 and- 31, commonly disposed facevtoface as indicated in Fig. 2,

with one end portion 32 of the member 30 engaging a shoulder 33 on the member 31. The thrust member 30 has a portion 35 projecting outward substantially perpendicular to one face thereof for-.a purpose to be described. 1

The member 30 also has an opening 37 therein through which extends an end por-.

tion of a retaining member 40. The body.

portion of the member 40 extends alongside and substantially parallel to the portion 35 of the thrust member 30. An offset projection 42 at one end of the member 40is seated in a pocket or recess 43 in the member-30 at also has a lug or projection 44 engaging, the outer face of the thrust member 31 and holding it in contact with the thrust member 30. A thermalelement 50 is inserted between the portion .35 of the member 30 and the retaining device 40. Whenpressure is applied at the ends of the locking member, as indicated bythe arrows wand 12 in .Fig. 2, it is obvious that the thermal element 50 will be held in compression.

J I. am thus enabled to use a low-melting solder, such as a mercury alloy, which could not be used in the ordinary construction where the thermal element is under tension instead of compression, as such low-melting alloys will yield and flow 'plastically under continued tension or even under continued shear, at normal temperatures. .When, however, such solder is under compression between comparatively large surfaces, this cold flowing practically ceases.

In order to prevent both corrosion and possible displacement of the parts, I commonly apply small amounts of solder, as indicated at s, to retain the several parts in assembled relation. The members 35 and 40 are preferably recessed, as indicated at55, so that, the walls being thinner, the device will be more quickly responsive to a rise in temperature.

Reference to Fig. 1 will show that when my improved locking member is in working position, the thermal element projects downward from the locking member directly into the path of a rising current of overheated air such as is indicated by the arrows c in Fig. 1. Consequently my improved locking member is very quickly responsive to a rise in temperature.

I find it desirable to form the thermal element with a recessed portion 56, as indicated in Fig. 7, as the greater part of the pressure is received by that part of the thermal element adjacent the outer ends of the members 35 and 40. With the recessed construction, less solder must be melted before the device will operate, while the interior space unfilled by solder is nevertheless not exposed to any corroding influences from without which might otherwise prevent movement of'the retaining device 40.

An important result of the arrangementof the component .parts of the strut as shown is that there is practically no diminution of the thrust of the compression screw 17 on the lever 15 and the ends of the locking member unti'lafter the angular .movement of the part leOhas enti'relyreleased the thrust member 31. At that instant all restraint is suddenly removed and hence the force of the screw becomes dynamic through the spring of the frame and the lever, post and strut arejerked free from each other even if corrosion has set in to an extent suflicient, in the absence of such suddenly applied force, to prevent the release of the parts. When the solder melts, the partsseparate, as indicated in Fig. 8, allowing the sprinkler to open and to become operative in the usual manner.

Having thus described my invention and the advantages thereof, I do .not wish to be limited to the.details herein disclosed, otherwisethan as set forth in thelclaims, but what and having offset lugs engaging oppositely disposed faces of'said two thrust members and a thermal element held in compression between said retaining device and said out wardly projecting portion of said thrust member, when arranged in operative position in said sprinkler head.

2. In a sprinkler head, a locking member i comprising two thrust membersdisposed face to face and having portions abutting endwise, one of said thrust members having a portion projecting outward from one face thereof, a

retaining device for said thrust members positioned alongside said outwardly projecting port-ion, and .a thermal element held in compression between said retaining device and said projecting portion, when arranged in operative position in said sprinkler head.

3. The combination in a locking member as set forth in claim 2, in which the thermal element is recessed to efi'ecte substantially U- shaped section.

4. In a sprinkler head, a locking member" 7 ment hasmelted and-said retainingdevice has completed its releasing movement.

5. In a sprinkler head, a locking member comprising two thrust members positioned face to face and having portions abutting endwise, aretainingdev-ice forsaid members, and a thermalelement formed of a low melting alloy and held in compression between said retaining device and'a portion ofione of said thrust members when said :partsiare .ar-

ranged in operative relation in a sprinkler head, said retaining device having a pivotal releasing movement about one end thereof when said thermal element melts and retaining said thrust members in abutting relation until said pivotal movement is substantially completed.

In testimony whereof I have hereuntoizr'fl fixed my signature.

GEORGE I. BOCKWOOFD. 

